1. Field of the Invention
The present invention relates generally to electrolytic pool chlorinators for chlorinating swimming pools of the like, and more particularly, to an electrolytic pool chlorinator incorporating a uniquely designed baffle to collect liberated chlorine gas while isolating undissolved salt from the anode of the chlorinator, and incorporating a packed column to intermix and react the liberated chlorine gas with a flow of water.
2. Description of the Prior Art
Electrolytic pool chlorinators are well known in the art and are exemplified by the following U.S. Pat. No. 914,856, issued to Meyer; No. 3,223,242, issued to Murray; No. 3,563,879, issued to Richards et al.; No. 4,097,356, issued to Yates; No. 4,256,552, issued to Sweeney; and No. 4,290,873, issued to Weaver. Such electrolytic pool chlorinators generally operate by electrolyzing a sodium chloride solution contained within an anode cell, attracting positively charged sodium ions to a negatively charged cathode and liberating chloride gas at the anode. The chlorine gas released thereby may then be used to chlorinate the water within a swimming pool, spa, or the like; the chlorine gas may also be used to chlorinate drinking water or sterilize sewage effluent.
The anode and cathode cells of such an electrolytic pool chlorinator are typically separated from one another by an ion-permeable barrier to prevent the liberated hydrogen and chlorine gas from mixing with one another and to minimize contamination of the sodium chloride solution within the anode cell by sodium hydroxide (caustic soda) formed within the cathode cell.
Once chlorine gas is generated within the anode cell, it must be intermixed within the body of water to be chlorinated to form hypochlorous acid in order to sterilize the water within the swimming pool or other body of water. U.S. Pat. No. 3,233,242 to Murray, and U.S. Pat. No. 4,290,873 to Weaver, each disclose a venturi formed within the water recirculating system of a swimming pool wherein a conduit communicating with the anode cell is coupled to a restricted throat portion of the venturi. A zone of low pressure is formed within the throat portion of the venturi due to the increased velocity of the water flowing therethrough for intermixing chlorine gas with the recirculated swimming pool water. However, such venturis require a relatively large volume of water to adequately withdraw chlorine gas from the anode cell of the electrolytic pool chlorinator and completely react such chlorine gas with the water.
While the water recirculation pipes normally used within most swimming pool systems to pump the pool water through a filter and back to a pool may have sufficient flow rates to permit such a venturi to be used to react the chlorine gas with the pool water, the formation of the venturi within such water recirculation pipes requires substantial modifications to such pipes. In addition, the formation of such a venturi within the swimming pool water recirculating pipes create additional back pressure on the recirculating pump, causing the pump to work harder. On the other hand, if only a portion of the recirculated water is diverted from the water recirculating pipes and caused to flow through a venturi, the reduced volume of water flowing through the venturi may be inadequate to completely react the liberated chlorine gas with the pool water; in this event, not only is some of the liberated chlorine gas wasted but also a safety problem may arise due either to accumulations of pressurized chlorine gas within various elements of the swimming pool or to leakage of unreacted chlorine gas therefrom.
U.S. Pat. No. 4,229,272 issued to Yates discloses a chlorine generator including a gas feed system having a tank constructed to receive chlorine gas and having a water inlet metered by a float valve. A gas trap region is formed by a downwardly depending plate into which the chlorine gas is introduced for mixing with the water in the tank. However, no mechanism is provided for actively reacting the chlorine gas with the water in the tank. U.S. Pat. No. 4,290,873 issued to Weaver describes a mixing cylinder for use with pool not having filter and pump systems. The mixing cylinder includes a venturi for suctioning chlorine gas into a flow of water and discharges the flow of water into the mixing cylinder. A float-controlled standpipe controls the outflow of water from the mixing cylinder.
Neither of the aforementioned U.S. Pat. Nos. 4,229,272 and 4,290,873 would appear to describe chlorine gas/water mixing apparatus which is capable of efficiently and completely reacting chlorine gas with relatively small quantities of water and thereby preventing dangerous accumulation of unreacted chlorine gas.
Prior art chlorinators are known to the present inventor wherein the anode chamber is vented to the atmosphere for preventing pressurized accumulations of chlorine gas within the upper portion of the anode chamber and for admitting air to prevent negative pressures from being created within the anode chamber when the liberated chlorine gas is suctioned at a rate faster than that at which it is being generated. However, such venting of the anode chamber may permit air to become mixed with the liberated chlorine gas and render it more difficult to react the liberated chlorine gas with water being returned to the pool.
Electrolytic pool chlorinators generate heat due to the electrical resistance within the electrolytic cell which opposes the conduction of current therein. Excessive heating of the chlorinator reduces its efficiency and tends to create caustic soda vapor within the cathode cell. This caustic soda vapor, if vented from the cathode cell, condenses upon the exterior of the chlorinator or the surrounding area and deposits dangerous caustic soda thereupon.
It is desirable to prevent accumulations of hydrogen gas within the cathode cell in view of the explosive nature of hydrogen gas. One manner of limiting accumulations of hydrogen gas within the cathode cell is to maintain the level of water within the cathode cell relatively near the upper end thereof, thereby limiting the available volume in which hydrogen gas may accumulate. It is also known in the art to provide a series of vents at the upper end of the cathode cell through which liberated hydrogen gas may be dispersed to the atmosphere. However, during operation of the electrolytic pool chlorinator, water within the anode cell tends to migrate toward the cathode cell, thereby raising the fluid level within the cathode cell; consequently, unless an overflow relief is provided, the cathode cell would ultimately become entirely filled by sodium hydroxide solution, eventually resulting in spillage of caustic soda through the hydrogen gas vents. U.S. Pat. No. 3,223,242 issued to Murray discloses an overflow outlet disposed within the upper end of the cathode cell for emptying excess sodium hydroxide solution from the cathode cell. Yet, Murray does not disclose any means for safely and conveniently disposing of the highly caustic sodium hydroxide solution which periodically overflows from the cathode cell.
Among those difficulties which have been experienced with prior art electrolytic pool chlorinators is the determination of the level of undissolved sodium chloride within the anode cell. Typically, the upper end of the anode cell is covered by a plate or lid which must be removed in order to view the contents of the anode cell. The need to remove the lid or plate covering the anode cell is often objectionable to the user due to the inconvenience necessitated thereby and the exposure of the user to latent chlorine fumes. Within U.S. Pat. No. 4,290,873 issued to Weaver, it is suggested that the amount of solid salt within the anode cell may be checked by the use of a pre-marked dip stick. However, the use of such a dip stick would require the displacement of the power supply housing disclosed by Weaver as well as the removal of a stopper inserted into the plate covering the anode cell; furthermore, this approach requires the user to maintain the dip stick readily available for periodically checking the salt level.
Another problem which has been experienced with many prior art electrolytic pool chlorinators has been the formation of salt cakes around the anode within the anode cell, which salt cakes interfere with the flow of current in the anode cell and result in the decreased efficiency or complete shutoff of the chlorinator. U.S. Pat. No. 3,563,879 issued to Richards et al discloses an anode cell wherein a perforated disc and a slotted, upwardly-extending sleeve divide the anode cell into a first portion containing the anode and a second portion for containing rock salt. While the aforementioned anode cell construction tends to reduce the amount of solid sodium chloride deposited near the anode, the perforations within the perforated disc and the slots within the slotted sleeve are large enough to permit smaller crystals of sodium chloride to pass therethrough and become deposited near the anode.
A further problem which has been encountered with prior art pool chlorinators is their tendency to destroy and/or render passive the specially constructed anode elements witin such chlorinators whenever the chlorinator is inadvertently operated after consuming all of the sodium chloride initially added to the anode cell. Operation of the chlorinator when the anode element is surrounded by water lacking sodium chloride results in the passivation of the anode element, typically requiring complete replacement thereof.
Yet another disadvantage of many prior art pool chlorinators is the build-up of chlorine fumes within the anode cell, which fumes are objectionable and potentially dangerous to users who must open the anode cell in order to service and maintain the chlorinator. Those skilled in the art will appreciate that a chlorinator which eliminates such objectionable chlorine gas fumes provides significant advantages over such prior art chlorinators.
In addition, prior art electrolytic chlorinators often do not provide convenient access to the principal components requiring periodic servicing or replacement. In particular, the anode element and the ion permeable barrier used to separate the anode and cathode cells from one another are often inaccessible or difficult to reach once the chlorinator has been manufactured. In some instances, the power supply components used to impose a voltage across the anode and cathode terminals are also difficult to access and are not separable from the electrolytic cell.
Accordingly, it is an object of the present invention to provide an electrolytic pool chlorinator which efficiently and completely mixes chlorine gas liberated therefrom with a flow of water directed into the pool of water to be chlorinated.
It is a further object of the present invention to provide such a pool chlorinator wherein a relatively small quantity of water under relatively low pressure is sufficient to completely react with the chlorine gas liberated by the chlorinator.
It is still another object of the present invention to collect chlorine gas liberated by the chlorinator in a manner which avoids the dilution of the liberated chlorine gas with air or other gases.
It is yet another object of the present invention to provide such a pool chlorinator wherein the flow of water into which the liberated chlorine gas is introduced also serves to remove heat from the pool chlorinator.
It is a further object of the present invention to provide such a pool chlorinator which prevents dangerous accumulations of both chlorine gas and hydrogen gas.
It is a still further object of the present invention to provide a means for safely and automatically disposing of sodium hydroxide solution which overflows from the cathode cell of the pool chlorinator.
Another object of the present invention is to provide such a pool chlorinator which reduces the likelihood of caustic soda vapor from escaping from the cathode cell thereof.
Yet another object of the present invention is to provide such a pool chlorinator which prevents solid sodium chloride within the anode cell thereof from forming salt cakes proximate the anode element or otherwise interfering with the exchange of ions between the anode and cathode cells.
It is yet another object of the present invention to provide such a pool chlorinator wherein the amount of undissolved sodium chloride contained with the anode cell of the chlorinator may be quickly and conveniently determined.
It is a further object of the present invention to provide such a pool chlorinator which substantially lessens the likelihood of the chlorinator being inadvertently operated after the water surrounding the anode element within the anode cell has become depleted of sodium chloride.
A further object of the present invention is to provide such a pool chlorinator meeting the above-described objects while being of simple and relatively inexpensive construction and providing convenient access to all components likely to require servicing or replacement.
These and other objects of the present invention will become more apparent to those skilled in the art as the description thereof proceeds.